In order to prevent water accumulating around the foundations of building structures from entering through the foundation walls, or otherwise, into the confines of the buildings, particularly into the lower parts thereof such as basements, it is customary to place drains adjacent to the foundations to carry accumulating water away before it rises to levels which would allow its entry into the buildings. Commonly, sections of abutting clay tiles are placed adjacent to the building footer for the purpose or more recently, use has been made of continuous flexible pipe fabricated from plastic-covered wire spiraling, perforated to admit accumulating water for disposal.
While the foregoing systems accomplish the drainage function, especially when initially installed, both have a tendency to admit dirt and silt with time, eventually becoming partially or totally plugged from such adventitiously entering material, impairing or destroying the draining efficiency.
Other drain systems have also been devised including that disclosed in my own prior U.S. Pat. No. 3,287,866, which comprehends drainage tiles positioned adjacent the inner face of an outer block wall footer. Openings are provided in the inner face of the block-wall so that water seeping into the wall can flow out to a gravel bed adjacent to the footer, and into drain tiles embedded therein. While the gravel bed retards the silting process, the drain tiles still eventually become plugged with silt or dirt, impeding the flow of the drain water therethrough. Furthermore, chemicals such as iron and lime, naturally present in the water, tend to accumulate on the gravel, while the gravel itself tends to settle and become tightly packed, both effects tending to slow down and prevent good drainage in the system.
Reference is also made to another of my prior patents, U.S. Pat. No. 4,612,742, relating to an improved wall and foundation drainage construction which utilizes a drainage member secured to an upper, inner surface of the footer and connecting to drainage openings provided in a bottom block of the wall, the drainage member extending out to gravel associated with drain tiles. While improved drainage action can be obtained from a construction of the type contemplated by the patent, to a degree, the system is still susceptible to the build-ups and plugging problems previously described.
Reference is also had to a still further of my prior patents, U.S. Pat. No. 4,590,722, which teaches a hollow drain member positioned in an earthen trench with a cover plate extending from a support on an adjacent foundation wall to the drain member. Although the invention described in the patent to a large extent avoids the plugging problems which afflict most drainage systems, the components of the system are relatively elaborate, and the installation of the system consequently not inexpensive.